Gas blast electric circuit breaker



Dec. 22, 1942. P. BARTLETT GAS BLAST ELECTRIC CIRCUIT BREAKER Filed July 25, 1941.

GAS BLAST ITM/ ntor: Percg Bartlett,

His Attorfneg.

Patented Dec. 22, 1942 p 2,306,242 Gas BLAST ELEc'rmocmoUn' Bananen l Percy Bartlett, springfield, Pa., assigner to Gen-v eral Electric Company, a corporation oi' New ork Application July 25, 1941, Serial No. 403,987 z claims. (ci. zoo-14s) My invention relates to gas blast electric circuit breakers, more particularly to those of the axial blast type v formed between separable contacts, at least one of which is hollow or tubular in form for receivgas blast to the point of My invention will be more fully set forth in the following description referring to the accompanying drawing, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this speciiication.

Referring to the drawing, Fig. 1 is an elevational view in section of a gas blast circuit breaker of the axial blast type embodying my invention in the closed circuit position thereof, and Fig. 2 is a similar view showing the breaker in'an initial stage of the opening operation.

The circuit breaker illustrated by way of example in Fig. 1 comprises relatively movable contact structure I and 2 in the form of tubular conductors separable to forman arc gap within an insulating housing 3 forming the arc chamber. The arc chamber is closed except for one or more gas blast supply conduits as indicated at 4 and the blast exhaust passages I' and 2 formed respectively by tubular extensions of the contacts I and 2.

For the purpose of operating the contacts, the contact I is provided with a piston 5 operable infa cylinder-like portion of the casing 3 arranged to be acted upon by the blast pressure The arcing or secondary contacts connected to the contacts I and 2 comprise a pair of conducting extensions 8 and 9 which are suitably secured to the contacts I and 2 respectively. The arcing contact 8 consists of an extension of the tubular part of the contact I cut on a bias as indicated at I0 and provided wherein the interrupting arc is on its inner surface with an arcing tip II of suitable arcresisting contact material, such as an alloy consisting of tungsten impregnated with copper. The coacting arcing contact 9 consists of a conducting stud the tip of indicated at I2, the arrangement permitting free iiow of exhaust gases through the contact 2.

contact 2, by suitable actuating means (not shown), the gas under pressure in the chamber 3 acts on the piston 5 to move the contact I- upward away from the contact 2 so `as to shunt the current through the arcing contacts 8 and 9.

Fig. 2 shows the sagement after initial separating movement of the contacts I and 2 at an intermediate point in the opening stroke. In this position, it will be noted that, although the contacts 8 and 9 are still in engagement, the blast exhaust passages I and 2' are in direct communication with the interior of the arc chamber by reason of the port at I0 that is opened upon initial movement of the contacts. 'I'his port admits the initial blast gas from the gas supply conduits I to the `exhaust passages prior to actual separation o1 the arcing contact structure so that the blast is in practically full motion at the very inception of the interrupting arc.

Consequently, when Vnot limited to speciiic details of construction arcing contacts still in enand arrangement thereof herein illustrated, and that changes and modiiications may occur `to one skilled in the art without departing from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A uid blast electric circuit breaker comprising an insulating arc chamber, relatively movable contact structures separable to form an arc gap in said chamber, means for directing an interrupting uid under pressure to said chamber, and means responsive to uid pressure in said chamber for causing separation of said contact structures, one of said contact structures being tubular to form an exhaust passage leading exteriorly oi said chamber from the region of said arc gap and the other of said contact structures normally closing said passage in the closed circuit position, said contact structures normally overlapping in sliding engagement when closed and being arranged upon initial opening movement thereof to uncover by slide valve action a port in one of said contact structures for admitting iiuid under pressure to said -passage prior to arcing caused by iinal separation oi the overlapping parts of said contact structures.

2. A gas blast electric circuit breaker comprising an insulating arc chamber, relatively movable main contacts, one of which is tubular for deiining an exhaust passage leading exterlorly of said chamber, separable to form an arc gap in said chamber, said passage being normally closed by said main contacts in the closed circuit position of said main contacts, means for directing an interrupting gas under pressure to said chamber, and means responsive to gas pressure in said chamber for causing separation of said contacts, said main contacts also having coacting arcing portions arranged in overlapping telescopic relation with respect to said main contacts so as to remain in contaqiaiter initial separating movement of said 'ain contacts, said main contacts thereupon opening said exhaust passage to initiate flow of the blast gas prior to separation of said arcing portions.

PERCY BARTLETT. 

